ABSTRACT Reducing exposure and building youth resiliency to child abuse and neglect (CAN), youth violence, teen dating violence (TDV), sexual assault, and self-harm/suicidality requires community-wide interventions. Targeted approaches to reduce specific subtypes of violence are costly, missing the overlap across violence. Further, extant individual interventions rely heavily on cognitive training. This project will provide scientific evidence through a field experiment concerning the effectiveness of a universal trauma-informed prevention intervention, HeartMath for Youth Resiliency and Violence Prevention, to build youth resiliency and prevent multiple forms of violence impacting children. The HeartMath Institute will deliver the teacher training and 4.5 month student intervention supported by a concurrent online parent training to teach basic neurophysiology concepts and techniques to build resilience, reduce stress, and reduce involvement in violence. Developing a universal intervention based on neurophysiological science to impact youth, educators, and families has the potential to streamline school-based resources for efficient violence prevention, thus saving costs and time for academic goals and providing fundamental skills for abused and neglected youth to break cycles of violence. In a one-year randomized controlled trial, we will test student main effects, subgroup effects for youth exposed to abuse and neglect at home, and educator effects of the program on resiliency and youth violence outcomes. Eighth grade educators in 40 schools in Texas Region 6, their students, and students' families are the target community. Schools will be randomized to universal treatment or control, and 2-3 random classrooms per school (n=1,800 students) selected for evaluation. Data sources are baseline and follow-up student and educator surveys and heart rate variability (a noninvasive biomeasure of resilience, and a key biofeedback component of the training), process data on technology usage, and practice logs. NORC will lead the evaluation with partner UTMB collecting on-site data. The hypotheses are that HeartMath will result in significantly (1) increased student and teacher resiliency and reductions in youth exposure to CAN and involvement in youth violence, sexual violence, TDV, and suicidal ideation; (2) greater program effects for students with CAN histories compared to peer students; and (3) greater educator resiliency and mentoring skills to survey as capable guardians for students. Outcomes will be assessed via multi-level structural equation models that estimate latent variables representing CAN exposure, resiliency, and violence profiles. Products include a final report, peer-reviewed articles, and a multi-tier dissemination plan for practitioners.